Suspended hot patch brick



March 23, 1965 J. w. LELAK 3,

SUSPENDED HOT PATCH BRICK Filed Jan. 27, 1964 2 Sheets-Sheet 1 Fig.3

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United States Patent 3,174,444 SUSPENDED HOT PATCH BRICK John W. Lelak, Pittsburgh, Pa., assignor to Harhison- Walker Refractories (Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 27, 1964, Ser. No. 340,190 6 Claims. (6i. 110-99) This invention relates to the hot patching of refractory roofs and to a novel hot patch roof shape. More particularly, the invention relates to a shape for the patching of hot open hearth roofs.

In the operation of industrial furnaces, such as the open hearth steel furnaces, glass melting furnaces and smelting and refining furnaces of the type used in the copper industry, environmental conditions exist which consume or destroy the refractory brick of which the roof is constructed. The temperatures in a furnace or other metallurgical vessel roof may be high enough to actually melt the refractories and their lower exposed surfaces so that they drip or run away and, thus, wear thin, resulting in an unstable roof. Sometimes holes are burned entirely through the roof. In some instances, the refractories may be eroded, due to slags and corrosive fumes and dusts which are present in the furnace atmosphere during operation thereof. Spalling may occur from thermal or mechanical shock. In any event, the result is to produce costly delays or to require termination of the operation of the furnace until repairs can be made to the roof. Frequently, it may be required that the entire roof be replaced, even though but a small area has been worn away or weakened. A particularly critical area of the roof, when it is of the arched type most commonly used in open hearth construction today, are the key brick. Key brick are the wedge-shaped ones which are used to complete an arched curve, the remainder of which is made of generally rectangular shapes.

It is among the objects of this invention to provide a means of prolonging the service life of a refractory roof and which permits the roof to be strengthened, or weakened areas to be entirely replaced, without taking the furnace off the line or even waiting for it to cool too much.

In accordance with this invention, a roof to which the invention applies is formed from a plurality of refractory brick disposed side-by-side in the usual manner. The brick are usually arranged in courses or alternating ribs and valleys, in the language of the steel maker or refractory technologist. A good example of an arched construction for open hearth roofs may be found, for example, in the publication Modern Refractory Practice, 4th edition, published by the Harbison-Walker Refractories Company and, in particular, the chapter beginning page 424.

When it is desired to repair a weakened area of the roof, which would normally be done a short time after a heat has been tapped from the furnace, the damaged or weakened area is broken out to form a generally rectangular or regular right polygon-shaped opening. A series of the composite brick of this invention are strung together on a rod or pipe and lowered into the opening. A series of such strings of the composite shapes can be fabricated, as desired, to fill the opening.

The composite shape, itself, is generally wedge-shaped when it is to be a key, although it can, of course, be of the regular rectangular shape if the patch is in a less critical area. The shape is usually a chemically bonded or unburned brick, although burned ones can be used. Considering the key, adjacent the upper and larger end, a notch is formed through an edge which extends entirely across the top of the shape. For example, in a brick having an upper end on the order of 3 X 4 /2", the notch extends across the 3" dimension.

3,174,444 Patented Mar. 23, 1965 A two-piece metal case is mounted about the notched brick. A first of the cases has an indentation formed adjacent that upper edge which is to be placed adjacent the notch formed in the brick. Preferably, the indentation has a flat lower edge or lip arranged to rest on the bottom of the notch in the brick. A slot-like aperture is formed through the rear wall of the indentation, a distance above the ledge. This first case is a generally U- shaped three-sided one, and is arranged to encompass a major portion of three side faces of the brick. A second U-shaped case is arranged to encompass two extending portions of the first case, and to cover the remaining fourth face of the brick. Adjacent an upper edge of this second case, which edge is to be placed adjacent the notch formed in the brick, an aperture is formed. The aperture allows free and unobstructed access to the indentation in the first case and the slot in the rear wall thereof. The rear wall through which the slot is formed is spaced from the real wall of the'brick notch. A pair of such composite shapes is arranged to be placed adjacent each other in such a manner that respective identations and slots are aligned. They are mounted on a single looped tab which, in cross section, resembles an inverted Dewar flask or bulb having an exaggerated lip about its opening. The enlarged tubular portion of the tab is arranged to receive a pipe or rod. The t-oes which extend from opposite sides of the bottom of the tab are arranged to penetrate the aligned slots of an adjacent pair of the composite shapes, whereby a rod can be' inserted through the enlarged portion of the tab to thereby support and suspend the attached pair of composite shapes.

A better understanding and other features and advantages of composite brick construction, and repair of hot roofs, according to this invention will be better understood by reference to the appended drawings. In these drawings,

FIG. 1 is a perspective view of a composite hot patch shape constructed according to this invention;

FIG. 2 is a perspective view of a refractory shape which can constitute a portion of the composite shape of FIG.

FIG. 3 is a planar view of a sheet metal blank which can be used to make a first of the pair of cases of the composite shape of FIG. 1;

FIG. 4 is a sheet metal blank from which the second case can be made;

FIG. 5 is a top view of the case blank of FIG. 4;

FIG. 6 is a fragmentary schematic view of a step in the patching of an open hearth roof with composite brick constructed according to this invention; and

FIG. 7 is a side elevation, with a portion of cases broken away, showing a pair of composite brick according to this invention in association with a preferred hanger tab.

Before describing the drawings in detail, it should be understood they are but exemplary of a preferred construction utilizing the concepts of this invention, and are not intended as limiting. Rather, the true spirit and scope of this invention is as defined in the hereafter appended claims.

A refractory brick 10 is shown in FIG. 1, which is encompassed by a pair of overlapping oxidizable metal cases 11 and 12. Each of these cases generally can be described as U-shaped. As is understood by those in the refractories and metallurgical arts, refractory shapes are usually described as having a hot face and a cold face. The cold face is that one to be furthest from the metallurgical process, and the hot face is that which is to be exposed to the metallurgical operation. Thus, in FIG. 1, the top face is the cold face or cold end and the bottom one is the hot face or hot end. A notch 13 has been cut out of one of the edges of the cold end. The notch is perpendicular to the larger side faces of the shape. Preferably, the lower face 13A and the back face 13B of the notch intersect at right angles. That rearwardly extending leg 11A of case 11 which covers the face through which the notch 13 is formed, has an indentation 15 formed in the cold end thereof. The bottom ledge or lip 16 of the indentation 15 is preferably flat, and extends perpendicularly or at right angles to the remainder of the leg 11A. A slot 17 is formed through the .rear wall of the indentation 15, and is spaced a short distance above the lip 16. Its center line is about Ms the distance above the lip 16. The rear wall of indentation 15 is spaced from notch wall 13B to allow later insertion of hanger means. The ledge 16, in cooperation with the face 13A of slot 13, assists in maintaining the case 11 in place on the brick 10, and serves to prevent loss of the case in service.

The second case 12, through its arm 12Awhich lies adjacent that side of brick 10 through which the notch 13 is formed, has an aperture 20 formed through its upper end. This aperture is of such size and is so positioned as to allow free and unrestricted access to slot 17 of indentation 15.

The case 12 is affixed to the case 11, as by spot welds 21. Of course, the two cases could be interconnected by punching ears through them after the composite shape is assembled. Further, the cases could be glued to the shape, but I do not suggest this. Still further, if one desired, instead of aperture 20, the leg 12A of case 12 could simply be a short leg having its entire upper end removed to a level just below or closely adjacent the ledge 16.

The composite shape of FIG. 1 is of generally rectangular configuration. It can be key-shaped; and, in fact, this is a particularly advantageous form of composite brick according to this invention. A roof key is larger at the top than at the bottom, and its smaller side surfaces have a converging taper, as shown, for example, by the refractory shape 30 of FIG. 2. The shape 30 has the notch 31 formed across its upper cold face at right angles to its larger side faces. Of course, the notch can be made in a brick or shape during the pressing operation. I prefer this. Alternatively, a regular six-sided shape can be machined or cut after removal from the brick press to form the notch.

The two channel-shaped cases of the composite shape vof FIG. 1 caneach be made from a fiat blank. For example, in FIG. 3, case 12 is shown as a flat sheet having the apertures 20 formed through the upper edge of an intended leg 12A. Score lines 35 and 36 are preferably formed across the plate to facilitate bending to form the desired U shape. Likewise, in FIG. 4, case 11 is shown in a sheet metal blank form. Score lines 37 and 38 are provided to facilitate latter bending to form the U shape, having a fiat web extending between two unidirectionallyextending legs. The indentation 15 is formed from or in the intended cold end, through an upper edge of side leg 11A. Slot 17 can be formed during the pressing of the indentation. FIG. provides a top view of the blank of FIG. 4.

In FIG. 7, a pair of identical composite shapes are shown in association with my preferred hanger tab 40. Those portions of the cases 11 and 12, which would obstruct a clear'view of the association between the tab 40 and the composite shapes, have been omitted for clarity of explanation. The hanger'40'is fabricated from a thin strip or strap of metal. It can be about 14 gauge, for example, and can be about /2" in width. The tab includes an enlarged upper tubular portion 41 having a downwardly extending pair of arms 42 and 43, which terminate in oppositely directed, upwardly extending fingers 44 and 45, which fingers are arranged to be inserted through the slots in the adjacent cases.

A pair of shapes can be lifted or suspended as shown in FIG. 6. When so suspended, a plurality of the composite shapes can be used to repair a roof. For example, in FIG. 6, an open hearth roof is shown from the top. An opening 51 has been broken through the roof 50 by removal of thin and weakened shapes, to form a generally rectangular hole or opening. Only sufiicient shapes are removed to make openings 51 as are necessary to expose good and desired thickness in the remaining roof brick 52. Of course, the opening 51 should be large enough to accommodate an even number of whole composite shapes. In FIG. 6, a rod is shown extending through a plurality of the hangers 40 with extending end portions 61 and 62 resting over adjacent portions of the remaining roof. This rod supports the pairs of composite brick in place until the furnace is subsequently heated, and adjacent metal cases fuse and oxidize to each other and to adjaceint remaining'brick 52 in the roof 50 to again form a strong and monolithic structure.

Because the composite shapes of this invention may be preassembled in units of groups of brick, it is simple for a worker or workers to climb on the top of the roof and rapidly drop them in place and align them without any special tools or expert instruction.

While I have shown square and flat surfaces for the notch 13 and indentation 16, it should, of course, be understood other complementary polarized male and female configurations can be used. However, I find the illustrated arrangement to be easiest and most economical. Further, I recommend complete sheathing of the four long side faces of the brick; but it is entirely possible to use a single U-shaped case such as case 11, above. Further, while I have shown two U-shaped cases, it is entirely feasible and, in some instances, desirable to use a one-piece blank which would wrap entirely about the brick. One end of this one-piece metal sheathing would have an aperture 20 formed in it and the other end an indentation 15 with its notch 17.

While I have shown each composite unit as comprised of one brick 10, it is feasible to include a plurality of brick within each unit as long as an end edge has the notch 13 or equivalent formed thereacross.

According to a preferred embodiment, the shapes 10 are unburned, chemically bonded refractory brick made of a mixture of dead burned magnesia and chrome ore. The magnesia constitutes about parts, by weight, of the brick, and the chrome ore the remaining 30% These refractory materials are size graded in the usual manner to make a brickmaking batch, mixed with a tempering agent of some manner; for example, lignin liquor, and formed on a brick press. An exemplary size grading would be about 30% of the total refractory batch 3+28 mesh, about 10% 28 mesh and resting on a 65 mesh screen, the remainder being -65 mesh or ball mill fines, as such a fraction is very often termed in the refractories art. Of this -65 mesh fraction, on the order of 40% to 60% will rest on a or 325 mesh screen.

Having thus described the invention in detail and with suificient particularity as to enable those skilled in the art to practice it, what is desired to have protected by Letters Patent is set forth in the following claims.

I claim:

1. A composite refractory member comprised of refractory brick and oxidizable metal casing therefor, said refractory brick having opposed ends and four side faces intersecting the ends to thereby define the brick, a notch formed through and entirely across an upper edge of the brick through an intersecting end and adjacent side, said notch defined by bricksurfaces which intersect at right angles, said casing'encompasing the major portion of the four sides of the brick and having an indentation formed therefrom, said indentation being adjacent and through an edge of said casing, said indentation characterized by a substantially flat-bottomed section and a substantially flat rear section which intersect each other at right angles, said bottom section intersecting the casing from which it is formed at right angles, the bottom section resting on a supporting surface which in part defines the notch and an aperture formed through said rear section adapted to receive hanger means, the rear section of said indentation being spaced away from an adjacent parallel surface of the notch formed in the refractory brick so as to allow insertion of a suspending portion of the hanger means.

2. The composite refractory member of claim 1 in which the oxidizable metal casing is comprised of two overlapping U-shaped metal cases, the indentation formed through a portion of a first of the cases which portion is in contiguous contact with an adjacent brick side face, that portion of the other case which overlaps that portion of the first case through which said indentation is formed, being itself cut away to expose said indentation.

3. A composite refractory member comprised of refractory brick and oxidizable metal casing therefor, said refractory brick having opposed ends and four side faces intersecting the ends to thereby define the brick, a notch formed through an upper edge of the brick through an intersecting end and adjacent side, said notch defined by brick surfaces which intersect at right angles, said casing encompassing the major portion of the four sides of the brick and having an indentation formed therefrom, said indentation being adjacent and through an edge of said casing, said indentation characterized by a substantially fiat-bottomed section and a substantially fiat rear section which intersect each other at right angles, said bottom section intersecting the casing from which it is formed at right angles, the bottom section resting on a supporting surface which in part defines the notch and an aperture formed through said rear section adapted to receive hanger means, the rear section of said indentation being spaced away from an adjacent parallel surface of the notch formed in the refractory brick so as to allow insertion of a suspending portion of the hanger means.

4. A composite refractory member comprised of refractory brick and oxidizable metal casing therefor, said refractory brick having opposed ends and four side faces intersecting the ends to thereby define the brick, a notch formed through an upper edge of the brick through an intersecting end and adjacent side, said notch defined by brick surfaces which intersect at right angles, said casing encompassing the major portion of at least three sides of the brick and having an indentation formed therefrom, said indentation being adjacent and through an edge of said casing, said indentation characterized by a substantially flat-bottomed section and a substantially flat rear section which intersect each other at right angles, said bottom section intersecting the casing from which it is formed at right angles, the bottom section resting on a supporting surface which in part defines the notch and an aperture formed through said rear section adapted to receive hanger means, the rear section of said indentation being spaced away from an adjacent parallel surface of the notch formed in the refractory brick so as to allow insertion of a suspending portion of the hanger means.

5. A composite refractory member comprised of refraotory brick and oxidizable metal casing therefor, said refractory brick having opposed ends and four side faces intersecting the ends to thereby define the brick, a notch formed through an upper edge of the brick through an intersecting end and adjacent side, said casing encompassing the major portion of at least three sides of the brick and having an indentation formed therefrom, said indentation characterized by a substantially flat-bottomed section and a substantially flat rear section, the bottom section resting on a supporting surface which in part define the notch and an aperture formed through said rear section adapted to receive hanger means, the rear section of said indentation being spaced away from an adjacent parallel surface of the notch formed in the refractory brick so as to allow insertion of a suspending portion of the hanger means.

6. A composite refractory member comprised of refractory brick and oxidizable metal casing therefor, said refractory brick having opposed ends and four side faces intersecting the ends to thereby define the brick, a notch formed through an upper edge of the brick through an intersecting end and adjacent side, said casing encom: passing the major portion of at least three sides of the brick and having an indentation formed therefrom, said indentation characterized by a bottom section and a rear section, the bottom section resting on a conforming. supporting surface which in part defines the notch and an aperture formed through said rear section adapted to receive hanger means, the rear section of said indentation being spaced away from an adjacent parallel surface of the notch formed in the refractory brick so as to allow insertion of a suspending portion of the hanger means.

References Cited by the Examiner UNITED STATES PATENTS 1,360,104 11/20 Faistenhammer 248-340 1,464,160 8/23 Weyel 248-340 2,840,017 6/58 Wolf -99 2,885,976 5/59 McGill et al 110-99 2,929,343 3/60 Hutter 110-99 3,029,755 4/62 Crichton 110-99 FOREIGN PATENTS 166,816 4/59 Sweden.

JAMES W. WESTHAVER, Primary Examiner. ROBERT A. DUA, Examiner. 

6. A COMPOSITE REFRACTORY MEMBER COMPRISED OF REFRACTORY BRICK AND OXIDIZABLE METAL CASING THEREFOR, SAID REFRACTORY BRICK HAVING OPPOSED ENDS AND FOUR SIDE FACES INTERSECTING THE ENDS TO THEREBY DEFINE THE BRICK, A NOTCH FORMED THROUGH AN UPPER EDGE OF THE BRICK THROUGH AN INTERSECTING END AND ADJACENT SIDE, SAID CASING ENCOMPASSING THE MAJOR PORTION OF AT LEAST THREE SIDES OF THE BRICK AND HAVING AN INDENTATION FORMED THEREFROM, SAID INDENTATION CHARACTERIZED BY A BOTTOM SECTION AND A REAR SECTION, THE BOTTOM SECTION RESTING ON A CONFORMING SUPPORTING SURFACE WHICH IN PART DEFINES THE NOTCH AND AN APERTURE FORMED THROUGH SAID REAR SECTION ADAPTED TO RECEIVE HANGER MEANS, THE REAR SECTION OF SAID INDENTATION BEING SPACED AWAY FROM AN ADJACENT PARALLEL SURFACE OF THE NOTCH FORMED IN THE REFACTORY BRICK SO AS TO ALLOW INSERTION OF A SUSPENDING PORTION OF THE HANGER MEANS. 